Transmitting apparatus and method

ABSTRACT

A communication device which can reduce amount of control information, limit interference with other traffics, and prevent an increase in current consumption. In this device, a separation unit separates radio resource allocation information, specific section information and transmission parameter information from a received signal. A specific section information control unit selects a sub-carrier designated by the specific section information to allocate data to be transmitted to the own unit. A channel quality measuring unit uses a pilot signal to measure the channel quality of the selected sub-carrier. A channel quality information creating unit creates channel quality information indicating the measurement results input from the channel quality measuring unit. A multiplexing unit multiplexes the transmission signal with the channel quality information.

TECHNICAL FIELD

The present invention relates to a communication apparatus and ascheduling method, and, more particularly, a communication apparatus, acommunication terminal apparatus and a scheduling method that areapplied to a communication scheme using frequency scheduling.

BACKGROUND ART

In high-speed wireless transmission, it is important to improveefficiency of signal transmission using flexible transmission controlthat can accommodate various traffic. Traffic control techniques includetime scheduling and frequency scheduling, and, for example, frequencyscheduling in MC-CDMA (multi-carrier CDMA) is being studied.

In MC-CDMA, a base station selects subcarriers that have good channelsbased on channel quality information such as SINR(signal-to-interference plus noise ratio) which is reported from aplurality of communication terminal apparatuses and transmits data.Users use the subcarriers that have good channel states, and thereforecommunication at a low PER (packet error rate) is possible.

Methods for controlling resources taking into consideration arequirement for delay have also been proposed (for example, PatentDocument 1). In such control methods, circuit-switching connections thataccompany bandwidths capable of dynamic control are allocated toconnections having strict requirements for a transmission delay. Afterresources are allocated to circuit-switching connections, resources areallocated from the unassigned resource pool to connections that have ahigh degree of allowance for a transmission delay.

-   Patent Document 1: Japanese Patent Publication Laid-Open No.    2001-512939

DISCLOSURE OF INVENTION Problems to be Solved by the Invention

In conventional apparatuses, however, the communication terminalapparatuses must report the channel quality information of allsubcarriers to the base station apparatus during frequency scheduling,and therefore there is a problem that the amount of uplink controlinformation increases and interference with other traffic increases.Conventional communication terminal apparatuses must also measure thechannel quality for all subcarriers, and therefore there is a problemthat current consumption increases due to signal processing formonitoring the channel. When conventional apparatuses are assumed toapply resource control that takes into consideration a requirement fordelay, users to which data allowing a delay is transmitted must continueto transmit control information just like users to which data notallowing a delay is transmitted, regardless of the lowered prioritylevel of transmission allocation. Therefore, there is a problem thatinterference due to the transmission of control information increasesand current consumption also increases due to the channel qualitymeasurement.

It is therefore an object of the present invention to provide acommunication apparatus and a scheduling method that can reduce theamount of control information, minimize interference with other traffic,and also prevent increases in current consumption.

Means for Solving the Problem

The communication apparatus of the present invention has a configurationincluding: a subcarrier selection section that selects subcarriers froma plurality of subcarriers within predetermined communication band; achannel quality measurement section that measures channel quality forthe subcarriers selected by the subcarrier selection section; and areport section that reports channel quality information to acommunicating party, the channel quality information being informationof the channel quality for the subcarriers measured by the channelquality measurement section.

The scheduling method of the present invention includes the steps of:selecting subcarriers from a plurality of subcarriers withinpredetermined communication band; measuring channel quality for theselected subcarriers; reporting channel quality information to acommunicating party, the channel quality information being informationof the channel quality for the measured subcarriers; and selecting atthe communicating party, subcarriers to which a transmission signal isallocated, based on the channel quality information.

Advantageous Effect of the Invention

According to the present invention, it is possible to reduce the amountof control information, minimize interference with other traffic, andprevent increases in current consumption.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the configuration of a communicationapparatus according to Embodiment 1 of the present invention;

FIG. 2 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 1 of the present invention;

FIG. 3 is a sequence diagram showing the operation of the communicationapparatus and the base station apparatus according to Embodiment 1 ofthe present invention;

FIG. 4 shows the relationship between frequency and channel qualityaccording to Embodiment 1 of the present invention;

FIG. 5 is a block diagram showing the configuration of a communicationapparatus according to Embodiment 2 of the present invention;

FIG. 6 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 2 of the present invention;

FIG. 7 is a sequence diagram showing the operation of the communicationapparatus and the base station apparatus according to Embodiment 2 ofthe present invention;

FIG. 8 is a block diagram showing the configuration of a communicationapparatus according to Embodiment 3 of the present invention;

FIG. 9 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 3 of the present invention;

FIG. 10 is a sequence diagram showing the operation of the communicationapparatus and the base station apparatus according to Embodiment 3 ofthe present invention;

FIG. 11 is a block diagram showing the configuration of a communicationapparatus according to Embodiment 4 of the present invention;

FIG. 12 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 4 of the present invention;

FIG. 13 shows the relationship between frequency and channel qualityaccording to Embodiment 4 of the present invention;

FIG. 14 is a block diagram showing the configuration of a communicationapparatus according to Embodiment 5 of the present invention; and

FIG. 15 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 5 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, embodiments of the present invention will be described in detailwith reference to the accompanying drawings.

Embodiment 1

FIG. 1 is a block diagram showing the configuration of communicationapparatus 100 according to Embodiment 1 of the present invention. In thepresent Embodiment 1, a case will be described as an example wherecommunication apparatus 100 is applied to a communication terminalapparatus.

Antenna 101 receives and outputs a signal to RF reception section 102and transmits the signal inputted from RF transmission section 112.

RF reception section 102 down-converts received signal inputted byantenna 101 from a radio frequency to a baseband frequency, and outputsthe result to demodulating section 103.

Demodulating section 103 demodulates received signal inputted from RFreception section 102 based on information of the modulation schemeincluded in the transmission parameter information inputted fromseparation section 105, which is described later, for the subcarriersindicated by the radio-resource allocation information inputted fromseparation section 105, and outputs the result to error-correctiondecoding section 104 and channel quality measuring section 107.Transmission parameter information is information of the modulationscheme and encoding rate allocated to each communication apparatus bythe base station apparatus, which is described later, and transmittedfrom the base station apparatus to each of the communicationapparatuses. Radio-resource allocation information is information of thesubcarriers selected by the base station apparatus based on channelquality, and transmitted from the base station apparatus to each of thecommunication apparatuses.

Error-correction decoding section 104 decodes and corrects errors of thereceived signal inputted from demodulating section 103 based oninformation of the encoding rate included in the transmission parameterinformation inputted from separation section 105, for the subcarriersindicated by the radio-resource allocation information inputted fromseparation section 105, and outputs the result to separation section105.

Separation section 105 separates radio-resource allocation information,specific segment information and transmission parameter information fromthe received signal inputted from error-correction decoding section 104.Separation section 105 outputs the separated specific segmentinformation to specific-segment information control section 106 andoutputs the radio-resource allocation information and transmissionparameter information to demodulating section 103 and error-correctiondecoding section 104. Separation section 105 also outputs the receivedsignal after separating the radio-resource allocation information, thespecific segment information and the transmission parameter information.Specific segment information is information of the subcarriers selectedby communication apparatus 100 indicated by the base station apparatusand transmitted from the base station apparatus to each of thecommunication apparatuses.

Specific-segment information control section 106, which is a subcarrierselection section, selects subcarriers which are indicated by thespecific segment information inputted from separation section 105, andto which data transmitted to communication apparatus 100 is allocated,and outputs information of the selected subcarriers to channel qualitymeasuring section 107. The method for selecting subcarriers will bedescribed later.

Channel quality measuring section 107 measures channel quality of theselected subcarriers from information of the subcarriers inputted fromspecific-segment information control section 106, using a pilot signalwhich is a known signal included in the received signal inputted fromdemodulating section 103. Channel quality measuring section 107 thenoutputs the measurement result to channel quality information generatingsection 108.

Channel quality information generating section 108 generates channelquality information, which is information indicating the measurementresult inputted from channel quality measuring section 107, and outputsthe generated channel quality information to multiplexing section 109.

Multiplexing section 109 multiplexes the received signal and the channelquality information inputted from channel quality information generatingsection 108 and outputs the result to error-correction encoding section110.

Error-correction encoding section 110 corrects errors and encodes themultiplexed transmission signal inputted from multiplexing section 109and outputs the result to modulating section 111.

Modulating section 111 modulates the transmission signal inputted fromerror-correction encoding section 110 and outputs the result to RFtransmission section 112.

RF transmission section 112 up-converts the transmission signal inputtedby modulating section 111 from a baseband frequency to a radio frequencyand outputs the result to antenna 101.

The configuration of base station apparatus 200, which is acommunicating party of communication apparatus 100, will be describedwith reference to FIG. 2. FIG. 2 is a block diagram showing theconfiguration of base station apparatus 200. FIG. 2 shows a case wherebase station apparatus 200 communicates with two communicationapparatuses 100, but base station apparatus 200 can also communicatewith an arbitrary number other than two, of communication apparatuses.In this case, transmission parameter setting sections 207 and 208,channel quality threshold setting sections 209 and 210, andspecific-segment allocation setting sections 211 and 212 may be providedwith the same numbers as the communication apparatuses that are incommunication.

Antenna 201 receives and outputs a signal to RF reception section 202and transmits the signal inputted from RF transmission section 216.

RF reception section 202 down-converts received signal inputted byantenna 201 from a radio frequency to a baseband frequency and outputsthe result to demodulating section 203.

Demodulating section 203 demodulates the received signal inputted fromRF reception section 202 and outputs the result to error-correctiondecoding section 204.

Error-correction decoding section 204 decodes and corrects errors in thereceived signal inputted from demodulating section 203 and outputs theresult to separation section 205.

Separation section 205 separates channel quality information for eachsubcarrier reported from each communication apparatus, from the receivedsignal inputted from error-correction decoding section 204. Separationsection 205 outputs the separated channel quality information of eachcommunication apparatus to resource allocating section 206 and outputsthe received signal after separating the channel quality information.

Resource allocating section 206 allocates resources—subcarriers—to eachcommunication apparatus based on the channel quality informationinputted from separation section 205 and the threshold value informationinputted from channel quality threshold setting sections 209 and 210,which are described later. At this time, resource allocating section 206excludes subcarriers for which channel quality information is notreported from communication apparatuses 100, from allocation targets.For example, resource allocating section 206 allocates subcarriers byselecting subcarriers in which the channel quality of the channelquality information at each communication apparatus 100 is equal to orgreater than the threshold value. Resource allocating section 206 thenoutputs radio-resource allocation information, which is information ofthe allocated subcarriers, to multiplexing section 213 and also outputsthe radio-resource allocation information for each communicationapparatus to transmission parameter setting sections 207 and 208.

Transmission parameter setting section 207 sets a transmission parametersuch as a modulation scheme and encoding rate in the subcarriers towhich the transmission signal is allocated, based on the radio-resourceallocation information inputted from resource allocating section 206.Transmission parameter setting section 207 then adds the settransmission parameter information to the transmission signal addressedto each communication apparatus and outputs the result to multiplexingsection 213. Transmission parameter setting section 207 also instructserror-correction encoding section 214 and modulating section 215 toprocess the transmission signal using the set transmission parameter.

Transmission parameter setting section 208 sets a transmission parametersuch as a modulation scheme and encoding rate in the subcarriers towhich the transmission signal is allocated, based on the radio-resourceallocation information inputted from resource allocating section 206.Transmission parameter setting section 208 then adds the settransmission parameter information to the transmission signal addressedto each communication apparatus and outputs the result to multiplexingsection 213. Transmission parameter setting section 208 also instructserror-correction encoding section 214 and modulating section 215 toprocess the transmission signal using the set transmission parameter.

Channel quality threshold setting section 209 sets a threshold valuebased on the QoS (quality of service) and traffic of the communicationapparatus and outputs the set threshold value information to resourceallocating section 206.

Channel quality threshold setting section 210 sets a threshold valuebased on the QoS and traffic of the communication apparatus and outputsthe set threshold value information to resource allocating section 206.

Specific-section allocation setting section 211 selects arbitrarysubcarriers from a plurality of subcarriers within predeterminedcommunication band based on the value such as QoS and traffic of thecommunication apparatus. Specific-segment allocation setting section 211then outputs specific segment information, which is information of theselected subcarriers, to multiplexing section 213.

Specific-segment allocation setting section 212 selects arbitrarysubcarriers from a plurality of subcarriers within predeterminedcommunication band based on the value such as QoS and traffic of thecommunication apparatus. Specific-segment allocation setting section 212then outputs specific segment information, which is information of theselected subcarriers, to multiplexing section 213.

Multiplexing section 213 multiplexes the transmission parameterinformation inputted from transmission parameter setting sections 207and 208, the specific segment information inputted from specific-segmentallocation setting sections 211 and 212, the radio-resource allocationinformation inputted from resource allocating section 206, and thetransmission signal, and outputs the result to error-correction encodingsection 214.

Error-correction encoding section 214 corrects errors and encodes themultiplexed transmission signal inputted from multiplexing section 213at the encoding rate indicated by transmission parameter settingsections 207 and 208 and outputs the result to modulating section 215.

Modulating section 215 modulates the transmission signal inputted fromerror-correction encoding section 214 at the modulation scheme indicatedby transmission parameter setting sections 207 and 208 and outputs theresult to RF transmission section 216.

RF transmission section 216 up-converts the transmission signal inputtedby modulating section 215 from a baseband frequency to a radio frequencyand outputs the result to antenna 201.

The operation of communication apparatus 100 and base station apparatus200 will be described next using FIG. 3. FIG. 3 is a sequence diagramshowing the operation of communication apparatus 100 and base stationapparatus 200, and the case will be described as an example where basestation apparatus 200 communicates with two communication apparatuses100. In FIG. 3, for the convenience of explanation, two communicationapparatuses 100 are indicated as MS#1 and MS#2, respectively, and basestation apparatus 200 is indicated as BTS. MS#1 and MS#2 have the sameconfiguration as FIG. 1, and BTS has the same configuration as FIG. 2.

BTS sets in advance a specific segment that accommodates users whichallow a delay at specific-segment allocation setting sections 211 and212 (controls specific segment allocation). When BTS transmits, forexample, data that cannot allow a delay to MS#1 and transmits data thatcan allow a delay to MS#2, specific-segment allocation setting section211 selects the specific segment that includes all subcarriers withinthe communication band, and BTS transmits to MS#1 the specific segmentinformation of the specific segment selected by specific-segmentallocation setting section 211 (step ST301). Specific-segment allocationsetting section 212 also selects a part of the subcarriers from theplurality of subcarriers within the communication band, and BTStransmits to MS#2 the specific segment information of the specificsegment selected by specific-segment allocation setting section 212(step ST302).

Next, MS#1, which receives the specific segment information, selects thesubcarriers indicated by the specific segment information atspecific-segment information control section 106, and measures thechannel quality for the selected subcarriers at channel qualitymeasuring section 107 (measures channel quality (of all resources)).FIG. 4 shows the relationship between frequency and channel qualitywithin communication band #411 of MS#1 and MS#2. Forty subcarriers #410are present within communication band #411 in FIG. 4, and five groups ofspecific segments #401, #402, #403, #404 and #405 are set withincommunication band #411. According to FIG. 4, MS#1 receives specificsegment information that selects all specific segments #401, #402, #403,#404 and #405, and therefore channel quality measuring section 107measures the channel quality for subcarriers #410 of all specificsegments #401, #402, #403, #404 and #405. MS#1 then reports measuredchannel quality #412 for subcarriers #410 of specific segments #401,#402, #403, #404 and #405 to BTS (step ST303).

Meanwhile, MS#2, which receives the specific segment information,selects the subcarriers indicated by the specific segment information atspecific-segment information control section 106, and measures thechannel quality for the selected subcarriers at channel qualitymeasuring section 107 (measures channel quality (for specificsegments)). According to FIG. 4, MS#2 receives specific segmentinformation that selects, for example, specific segment #402, andchannel quality measuring section 107 measures the channel quality forsubcarriers #410 of specific segment #402. MS#2 then reports measuredchannel quality #413 for subcarriers #410 of specific segment #402 toBTS (step ST304).

BTS receives the channel quality information of channel quality #412 and#413 and allocates resources to MS#1 at resource allocating section 206in accordance with channel quality #412 for subcarriers of specificsegments #401, #402, #403, #404 and #405 (controls resource allocationbased on the channel quality). At this time, channel quality #412 is ofhigher quality than channel quality #413, and BTS performs allocationprocessing in accordance with the requirement for delay, and thereforeresources can be allocated to MS#1 to which data that does not allow adelay is transmitted, but resources cannot be allocated to MS#2. BTStherefore transmits transmission parameter information only to MS#1(step ST305). BTS then processes the transmission signal to betransmitted to MS#1 based on the transmission parameter set bytransmission parameter setting section 207 (transmission processing forMS#1). BTS then transmits the transmission signal to MS#1 (step ST306).MS#1 receives the transmission parameter information and thetransmission signal, processes the received signal (receptionprocessing), confirms that demodulation is successful, and returns areception response to BTS (step ST307).

MS#1 then measures channel quality #412 for subcarriers of specificsegments #401, #402, #403, #404 and #405 of the specific segmentinformation received in step ST301 at channel quality measuring section107 (measures channel quality (for all resources)) and reports thechannel quality information to BTS (step ST308). MS#2 also measureschannel quality #414 for the subcarriers of specific segment #402 of thespecific segment information received in step ST302 at channel qualitymeasuring section 107 (measures channel quality (for specific segments))and reports the channel quality information to BTS (step ST309).

The channel quality for specific segment #402 is of higher channelquality for MS#2 than for MS#1, and therefore BTS which receives thechannel quality information of channel quality #412 and #414 nextallocates resources to MS#1 at resource allocating section 206 inaccordance with channel quality #412 for the subcarriers of specificsegments #401, #403, #404 and #405 and allocates resources to MS#2 inaccordance with channel quality #414 for the subcarriers of specificsegment #402 (controls resource allocation based on the channelquality). BTS therefore transmits transmission parameter information ofthe subcarriers of specific segments #401, #403, #404 and #405 to MS#1(step ST310) and transmits transmission parameter information of thesubcarriers of specific segment #402 to MS#2 (step ST311).

BTS then processes the transmission signal to be transmitted to MS#1based on the transmission parameter set by transmission parametersetting section 207 (transmission processing for MS#1) and processes thetransmission signal to be transmitted to MS#2 based on the transmissionparameter set by transmission parameter setting section 208(transmission processing for MS#2). BTS then transmits the transmissionsignal to MS#1 (step ST312) and the transmission signal to MS#2 (stepST313). MS#1 then receives the transmission parameter information andthe transmission signal, processes the received signal (receptionprocessing), and returns a reception response to BTS (step ST314). MS#2also receives the transmission parameter information and thetransmission signal, processes the received signal (receptionprocessing), confirms that demodulation is successful, and returns areception response to BTS (step ST315).

MS#1 performs predetermined processing assuming that communication iscomplete at the second transmission addressed to MS#1 (receptioncompletion processing), and after that, does not measure quality. MS#2measures channel quality #414 for the subcarriers of specific segment#402 of the specific segment information received in step ST302 atchannel quality measuring section 107 (measures channel quality (forspecific segments)) and reports the channel quality information to BTS(step ST316)). Similar processing is repeated thereafter.

According to the present Embodiment 1, the communication terminalapparatus only measures and reports to the base station apparatus thechannel quality for the subcarriers indicated by the base stationapparatus, so that it is possible to reduce the amount of controlinformation, minimize interference with other traffic, and preventincreases in current consumption.

Embodiment 2

FIG. 5 is a block diagram showing the configuration of communicationapparatus 500 according to Embodiment 2 of the present invention. In thepresent Embodiment 2, the case will be described as an example wherecommunication apparatus 500 is applied to a communication terminalapparatus.

In communication apparatus 500 according to the present Embodiment 2,specific-segment information control section 106 is removed fromcommunication apparatus 100 according to Embodiment 1 shown in FIG. 1,and specific-segment-related information control section 501 is added asshown in FIG. 5. In FIG. 5, components that are the same as those inFIG. 1 will be assigned the same reference numerals without furtherexplanations.

Separation section 105 separates radio-resource allocation information,specific segment information, specific segment validity periodinformation, and transmission parameter information from the receivedsignal inputted from error-correction decoding section 104, outputs theseparated specific segment information and specific segment validityperiod information to specific-segment-related information controlsection 501 and outputs the radio-resource allocation information andtransmission parameter information to demodulating section 103 anderror-correction decoding section 104. Separation section 105 alsooutputs the received signal after separating the radio-resourceallocation information, the specific segment information, the specificsegment validity period information and the transmission parameterinformation. Specific segment validity period information in this caseis information for specifying a predetermined period for selectingsubcarriers indicated by the base station apparatus and transmitted fromthe base station apparatus to each of the communication apparatuses.

Specific-segment-related information control section 501 selectssubcarriers to which data transmitted to communication apparatus 500 isallocated, based on the specific segment information inputted fromseparation section 105 and within the specific segment validity period(specific segment selection period) indicated by the specific segmentvalidity period information inputted from separation section 105.Specifically, specific-segment-related information control section 501selects the subcarriers indicated by the specific segment informationwithin the period indicated by the specific segment validity periodinformation, and selects all subcarriers within predeterminedcommunication band within a period not indicated by the specific segmentvalidity period information. Specific-segment-related informationcontrol section 501 then outputs information of the selected subcarriersto channel quality measuring section 107. The method for selectingsubcarriers will be described later. When the subcarriers selected bythe specific segment information are indicated for all periods, the basestation apparatus need not transmit specific segment validity periodinformation.

Channel quality measuring section 107 measures channel quality for theselected subcarriers from information of the subcarriers inputted fromspecific-segment-related information control section 501 using a pilotsignal which is a known signal included in the received signal inputtedfrom demodulating section 103. Channel quality measuring section 107then outputs the measurement result to channel quality informationgenerating section 108.

The configuration of base station apparatus 600 will be described nextusing FIG. 6. FIG. 6 is a block diagram showing the configuration ofbase station apparatus 600.

As shown in FIG. 6, base station apparatus 600 according to the presentEmbodiment 2 has multiplexing section 601 instead of multiplexingsection 213 of base station apparatus 200 according to Embodiment 1shown in FIG. 2. In FIG. 6, components that are the same as those inFIG. 2 will be assigned the same reference numerals without furtherexplanations.

Transmission parameter setting section 207 sets a transmission parametersuch as a modulation scheme and encoding rate in the subcarriers towhich transmission signal is allocated, based on the radio-resourceallocation information inputted from resource allocating section 206.Transmission parameter setting section 207 then adds the settransmission parameter information to the transmission signal addressedto each communication apparatus, outputs the result to multiplexingsection 601, and instructs error-correction encoding section 214 andmodulating section 215 to process the transmission signal using the settransmission parameter.

Transmission parameter setting section 208 sets a transmission parametersuch as a modulation scheme and encoding rate in the subcarriers towhich transmission signal is allocated, based on the radio-resourceallocation information inputted from resource allocating section 206.Transmission parameter setting section 208 then adds the settransmission parameter information to the transmission signal addressedto each communication apparatus, outputs the result to multiplexingsection 601, and instructs error-correction encoding section 214 andmodulating section 215 to process the transmission signal using the settransmission parameter.

Specific-segment allocation setting section 211 selects arbitrarysubcarriers from a plurality of subcarriers within predeterminedcommunication band based on the value such as QoS and traffic of thecommunication apparatus. Specific-segment allocation setting section 211then outputs specific segment information, which is information of theselected subcarriers, to multiplexing section 601.

Specific-segment allocation setting section 212 selects arbitrarysubcarriers from a plurality of subcarriers within predeterminedcommunication band based on the value such as QoS and traffic of thecommunication apparatus. Specific-segment allocation setting section 212then outputs specific segment information, which is information of theselected subcarriers, to multiplexing section 601.

Multiplexing section 601 multiplexes the transmission parameterinformation inputted from transmission parameter setting sections 207and 208, the specific segment information inputted from specific-segmentallocation setting sections 211 and 212, the radio-resource allocationinformation inputted from resource allocating section 206, the specificsegment validity period information, and the transmission signal, andoutputs the result to error-correction encoding section 214.

Error-correction encoding section 214 corrects errors and encodes themultiplexed transmission signal inputted from multiplexing section 601at the encoding rate indicated by transmission parameter setting section208 and outputs the result to modulating section 215.

The operation of communication apparatus 500 and base station apparatus600 will be described next using FIG. 7. FIG. 7 is a sequence diagramshowing the operation of communication apparatus 500 and base stationapparatus 600, and the case will be described as an example where basestation apparatus 600 communicates with two communication apparatuses500. In FIG. 7, for the convenience of explanation, two communicationapparatuses 500 are indicated as MS#1 and MS#2, respectively, and basestation apparatus 600 is indicated as BTS. MS#1 and MS#2 have the sameconfiguration as FIG. 5, and BTS has the same configuration as FIG. 6.

BTS sets in advance a specific segment that accommodates users that willallow a delay (controls specific segment allocation) at specific-segmentallocation setting sections 211 and 212 and sets specific segmentvalidity period #701, which is the processing period for setting thespecific segment (sets specific segment timer). BTS thereby performsprocessing for selecting a specific segment within specific segmentvalidity period #701 and does not perform processing for selecting aspecific segment in a period other than specific segment validity period#701. BTS does not change the specific segment information reported toMS#1 and MS#2 during specific segment validity period #701. Thesubcarriers of the specific segment information can be made to changeeach time the specific segment validity period is set, or thesubcarriers of the specific segment information can be made to be leftunchanged in a period during which the specific segment validity periodis set a predetermined number of times. In FIG. 7, the case has beendescribed where the specific segment validity period is set once, butthe specific segment validity period may be set a plurality of timeswithin a predetermined period. The subsequent operation is the same asin FIG. 3, and therefore a description of that operation will beomitted.

According to the present Embodiment 2, the base station apparatus sets aspecific segment validity period within a predetermined period, andtherefore, in addition to the effects of the above-described Embodiment1, it is possible to appropriately control resource distribution for thespecific segment allocation for each specific segment validity period.According to the present Embodiment 2, the measuring segment need not bechanged in the communication apparatuses during the specific segmentvalidity period indicated by the base station apparatus, and thereforeprocessing in the communication apparatuses can be simplified.

Embodiment 3

FIG. 8 is a block diagram showing the configuration of communicationapparatus 800 according to Embodiment 3 of the present invention. In thepresent Embodiment 3, the case will be described as an example wherecommunication apparatus 800 is applied to a communication terminalapparatus.

In communication apparatus 800 according to the present Embodiment 3,specific-segment information control section 106 is removed fromcommunication apparatus 100 according to Embodiment 1 shown in FIG. 1,and specific-segment information generating section 801 is added asshown in FIG. 8. In FIG. 8, components that are the same as those inFIG. 1 will be assigned the same reference numerals.

Separation section 105 separates radio-resource allocation informationand transmission parameter information from the received signal inputtedfrom error-correction decoding section 104 and outputs the separatedradio-resource allocation information and transmission parameterinformation to demodulating section 103 and error-correction decodingsection 104. Separation section 105 also separates QoS information,which is information as to whether or not data transmitted tocommunication apparatus 800 can allow a delay, from the received signalinputted from error-correction decoding section 104 and outputs theseparated QoS information to specific-segment information generatingsection 801. Separation section 105 also outputs the received signalafter separating the QoS information, the radio-resource allocationinformation and the transmission parameter information.

When the data transmitted to communication apparatus 800 can allow adelay according to the QoS information inputted from separation section105, specific-segment information generating section 801 selects fromthe subcarriers within predetermined communication band subcarriers towhich the data transmitted to communication apparatus 800 is allocatedand outputs information of the selected subcarriers to channel qualitymeasuring section 107. When the data transmitted to communicationapparatus 800 cannot allow a delay according to the QoS informationinputted from separation section 105, specific-segment informationgenerating section 801 selects all subcarriers within the communicationband as subcarriers to which the data transmitted to the communicationapparatus is allocated and outputs information of the selectedsubcarriers to channel quality measuring section 107. When the QoSinformation indicates that the data transmitted to communicationapparatus 800 can allow a delay, specific-segment information generatingsection 801 also outputs information of the selected subcarriers tomultiplexing section 109 as specific segment information.

Channel quality measuring section 107 measures channel quality for theselected subcarriers according to information of the subcarriersinputted from specific-segment information generating section 801, usinga pilot signal, which is a known signal included in the received signalinputted from demodulating section 103. Channel quality measuringsection 107 then outputs the measurement result to channel qualityinformation generating section 108.

Multiplexing section 109 multiplexes the received signal, the channelquality information inputted from channel quality information generatingsection 108, and the specific segment information inputted fromspecific-segment information generating section 801, and outputs theresult to error-correction encoding section 110.

The configuration of base station apparatus 900 will be described nextusing FIG. 9. FIG. 9 is a block diagram showing the configuration ofbase station apparatus 900. In base station apparatus 900 according tothe present Embodiment 2, specific-segment allocation setting section211 and specific-segment allocation setting section 212 are removed frombase station apparatus 200 of Embodiment 1 shown in FIG. 2, andspecific-segment information control section 901 is added as shown inFIG. 9. In FIG. 9, components that are the same as those in FIG. 2 willbe assigned the same reference numerals without further explanations.

Separation section 205 separates channel quality information andspecific segment information for each subcarrier reported from eachcommunication apparatus, from the received signal inputted fromerror-correction decoding section 204. Separation section 205 outputsthe separated channel quality information of each communicationapparatus to resource allocating section 206 and outputs the separatedspecific segment information of each communication apparatus tospecific-segment information control section 901. Separation section 205also outputs the received signal after separating the channel qualityinformation and the specific segment information.

Specific-segment information control section 901 instructs resourceallocating section 206 to perform resource allocation within the rangeof subcarriers that are selected by communication apparatus 800 andreported in the specific segment information inputted from separationsection 205.

Resource allocating section 206 allocates resources—subcarriers—to thecommunication apparatuses based on the channel quality informationinputted from separation section 205 and the threshold value informationinputted from channel quality threshold setting sections 209 and 210,for the subcarriers indicated by specific-segment information controlsection 901. Resource allocating section 206 then outputs radio-resourceallocation information, which is information of the allocatedsubcarriers, to multiplexing section 213 and also outputs radio-resourceallocation information for each communication apparatus to transmissionparameter setting sections 207 and 208.

Multiplexing section 213 multiplexes the transmission parameterinformation inputted from transmission parameter setting sections 207and 208, the radio-resource allocation information inputted fromresource allocating section 206, the QoS information, and thetransmission signal, and outputs the result to error-correction encodingsection 214. Judgment as to whether or not the data in the QoSinformation can allow a delay is made by comparing the predeterminedthreshold value and the delay time that the data can allow. For example,if the allowable delay time is equal to or greater than the thresholdvalue, judgment is made that the data can allow a delay.

The operation of communication apparatus 800 and base station apparatus900 will be described next using FIG. 10. FIG. 10 is a sequence diagramshowing the operation of communication apparatus 800 and base stationapparatus 900, and the case will be described as an example where basestation apparatus 900 communicates with two communication apparatuses800. In FIG. 10, for the convenience of explanation, two communicationapparatuses 800 are indicated as MS#1 and MS#2, respectively, and basestation apparatus 900 is indicated as BTS. MS#1 and MS#2 have the sameconfiguration as FIG. 8, and BTS has the same configuration as FIG. 9.

BTS transmits the QoS information of MS#1 to MS#1 (step ST1001). BTSalso transmits the QoS information of MS#2 to MS#2 (step ST1002). Inthis case, the QoS information transmitted to MS#1 indicates that datathat cannot allow a delay will be transmitted, and the QoS informationtransmitted to MS#2 indicates that data that can allow a delay will betransmitted. The data addressed to MS#1 cannot allow a delay, andtherefore MS#1 which receives the QoS information does not generatespecific segment information at specific-segment information generatingsection 801. Meanwhile, the data transmitted to MS#2 can allow a delay,and therefore MS#2 which receives the QoS information generates specificsegment information at specific-segment information generating section801. MS#2 then transmits the generated specific segment information toBTS (step ST1003).

MS#1 which does not transmit specific segment information measures thechannel quality for all subcarriers within the communication band(measures channel quality (for all resources)). For example, accordingto FIG. 4, MS#1 measures the channel quality for subcarriers #410 of allspecific segments #401, #402, #403, #404 and #405 at channel qualitymeasuring section 107. MS#1 then reports channel quality #412 forsubcarriers #410 of measured specific segments #401, #402, #403, #404and #405 to BTS (step ST303).

Meanwhile, MS#2 which transmits specific segment information measuresthe channel quality for the subcarriers of the specific segments of thespecific segment information transmitted to BTS (measures channelquality (for specific segments)). For example, according to FIG. 4, whenMS#2 transmits the specific segment information of specific segment #402to BTS, channel quality measuring section 107 measures the channelquality for subcarriers #410 of specific segment #402. MS#2 then reportschannel quality #413 for subcarriers #410 of measured specific segment#402 to BTS (step ST304). The subsequent operation of FIG. 10 is thesame as in FIG. 3, and therefore the same reference numerals as in FIG.3 will be assigned without further explanations.

According to the present Embodiment 3, when data that allows a delay istransmitted to the communication apparatus, the communication apparatusselects a part of the subcarriers within the communication band andmeasures only channel quality for the selected subcarriers and reportsthe channel quality to the base station apparatus, so that it ispossible to reduce the amount of control information, minimizeinterference with other traffic, and prevent increases in currentconsumption.

In the present Embodiment 3, Qos information transmitted from basestation apparatus 900 includes information of a judgment result as towhether data can allow a delay, but this is by no means limiting, andQos information may include information of an allowable time, andspecific-segment information generating section 801 of communicationapparatus 800 may compare between the allowable time of the Qosinformation and a threshold value, and, when the allowable time is equalto or greater than the threshold value, judgment is made that the datacan allow a delay.

Embodiment 4

FIG. 11 is a block diagram showing the configuration of communicationapparatus 1100 according to Embodiment 4 of the present invention. Inthe present Embodiment 4, the case will be described as an example wherecommunication apparatus 1100 is applied to a communication terminalapparatus.

In communication apparatus 1100 according to the present Embodiment 4,measurement-range class control section 1101 as shown in FIG. 11 isadded to communication apparatus 100 according to Embodiment 1 shown inFIG. 1. In FIG. 11, components that are the same as those in FIG. 1 willbe assigned the same reference numerals without further explanations.

Separation section 105 separates radio-resource allocation informationand transmission parameter information from the received signal inputtedfrom error-correction decoding section 104 and outputs the separatedradio-resource allocation information and transmission parameterinformation to demodulating section 103 and error-correction decodingsection 104. Separation section 105 also separates measurement-rangeclass information which is information indicating in stages theallowable delay time for the data transmitted to communication apparatus1100, from the received signal inputted from error-correction decodingsection 104 and outputs the separated measurement-range classinformation to measurement-range class control section 1101. Separationsection 105 also outputs the received signal after separating themeasurement-range class information, the radio-resource allocationinformation and the transmission parameter information.Measurement-range class information will be described in more detaillater.

Measurement-range class control section 1101 stores the same informationfor selecting a measurement range as the base station apparatus, inwhich the measurement-range class and measurement range are associated,and selects a measurement range referring to the information forselecting a measurement range using measurement-range class informationinputted from separation section 105. Measurement-range class controlsection 1101 then outputs information of the selected measurement rangeto specific-segment information control section 106.

Specific-segment information control section 106 selects subcarriers towhich data transmitted to communication apparatus 1100 is allocated, foreach measurement range, from information of the measurement rangeinputted from measurement-range class control section 1101, and outputsinformation of the selected subcarrier to channel quality measuringsection 107. The method for selecting subcarriers will be describedlater.

The configuration of base station apparatus 1200 will be described nextusing FIG. 12. FIG. 12 is a block diagram showing the configuration ofbase station apparatus 1200.

In base station apparatus 1200 according to the present Embodiment 4,specific-segment allocation setting sections 211 and 212 are removedfrom base station apparatus 200 according to Embodiment 1 shown in FIG.2, and measurement-range class control sections 1201 and 1202 are addedas shown in FIG. 12. In FIG. 12, components that are the same as thosein FIG. 2 will be assigned the same reference numerals without furtherexplanations. FIG. 12 shows the case where base station apparatus 1200communicates with two communication apparatuses 1100, but base stationapparatus 1200 can also communicate with an arbitrary number other thantwo, of communication apparatuses. In this case, transmission parametersetting sections 207 and 208, channel quality threshold setting sections209 and 210, and measurement-range class control sections 1201 and 1202may be provided with the same number as the communication apparatusesthat are in communication.

Measurement-range class control section 1201 stores the same informationfor selecting a measurement range as measurement-range class controlsection 1101, selects a measurement range from the measurement rangesset in stages for each allowable delay, based on the value such as QoSand traffic of the communication apparatus, and outputs information ofthe selected measurement range to multiplexing section 213 asmeasurement-range class information.

Measurement-range class control section 1202 stores the same informationfor selecting a measurement range as measurement-range class controlsection 1101, selects a measurement range from the measurement rangesset in stages for each allowable delay based on the value such as QoSand traffic of the communication apparatus, and outputs information ofthe selected measurement range to multiplexing section 213 asmeasurement-range class information.

The method for selecting subcarriers will be described next. FIG. 13shows the relationship between frequency and channel quality withincommunication band #1311 of MS#1 and MS#2. Forty subcarriers #1310 arepresent within communication band #1311 in FIG. 13, and five specificsegments #1301, #1302, #1303, #1304 and #1305 are set withincommunication band #1311. In the measurement-range class information,delay allowance class 1 selects specific segment #1302, delay allowanceclass 2 selects specific segments #1301 and #1302, and delay allowanceclass 3 selects specific segments #1301, #1302, #1303 and #1304, thatis, all the subcarriers within communication band #1311. Delay allowanceclass 1 includes the largest allowable delay time, delay allowance class3 includes the smallest allowable delay time, and delay allowance class2 includes a smaller allowable delay time than delay allowance class 1and a larger allowable delay time than delay allowable class 3.Subcarriers to which data is allocated are thus reduced in accordancewith an increase in the allowable delay time of the data.

According to FIG. 13, base station apparatus 1200 transmits, forexample, the measurement-range class information of delay allowanceclass 1 to communication apparatus 1100 that transmits data having alarge allowable delay time, and transmits the measurement-range classinformation of delay allowance class 3 to communication apparatus 1100that transmits data having a small allowable delay time. Other than thefact that measurement ranges are allocated instead of specific segmentsand measurement-range class information is transmitted instead ofspecific segment information, the operation of communication apparatus1100 and base station apparatus 1200 is the same as in FIG. 3, andtherefore a description of that operation will be omitted.

According to the present Embodiment 4, subcarriers are divided intogroups for each measurement range, and measurement ranges are selectedaccording to the allowable delay time, so that, in addition to theeffects of the above-described Embodiment 1, subcarrier frequencyscheduling can be accurately performed in accordance with the allowabledelay time. According to the present Embodiment 4, the communicationapparatus can select subcarriers by transmitting measurement-range classinformation from the base station, so that it is possible to simplifythe processing for selecting subcarriers.

Embodiment 5

FIG. 14 is a block diagram showing the configuration of communicationapparatus 1400 according to Embodiment 5 of the present invention. Inthe present Embodiment 5, the case will be described as an example wherecommunication apparatus 1400 is applied to a communication terminalapparatus.

In communication apparatus 1400 according to the present Embodiment 5,specific-segment information control section 106 is removed fromcommunication apparatus 100 according to Embodiment 1 shown in FIG. 1,and measurement-range class control section 1401 and specific-segmentinformation generating section 1402 are added as shown in FIG. 14. InFIG. 14, components that are the same as those in FIG. 1 will beassigned the same reference numerals without further explanations.

Separation section 105 separates radio-resource allocation informationand transmission parameter information from the received signal inputtedfrom error-correction decoding section 104 and outputs the separatedradio-resource allocation information and transmission parameterinformation to demodulating section 103 and error-correction decodingsection 104. Separation section 105 also separates QoS information,which is information indicating the allowable delay time of the datatransmitted to communication apparatus 1400, from the received signalinputted from error-correction decoding section 104 and outputs theseparated QoS information to measurement-range class control section1401. Separation section 105 also outputs the received signal afterseparating the QoS information, the radio-resource allocationinformation and the transmission parameter information.

Measurement-range class control section 1401 stores the same informationfor selecting a measurement range as the base station apparatus, inwhich measurement-range class and measurement range for each allowabledelay time are associated, and selects a measurement range according tothe allowable delay time referring to the information for selecting ameasurement range using the Qos information inputted from separationsection 105. Measurement-range class control section 1401 then outputsinformation of the selected measurement range to specific-segmentinformation generating section 1402 and multiplexing section 109.

Specific-segment information control section 1402 selects thesubcarriers of the measurement ranges as subcarriers to which datatransmitted to communication apparatus 1400 is allocated, according tothe information of measurement ranges inputted from measurement-rangeclass control section 1401 and outputs information of the selectedsubcarriers to channel quality measuring section 107.

Channel quality measuring section 107 measures channel quality for theselected subcarriers from the information of the subcarriers inputtedfrom specific-segment information generating section 1402 using a pilotsignal which is a known signal included in the received signal inputtedfrom demodulating section 103. Channel quality measuring section 107then outputs the measurement result to channel quality informationgenerating section 108.

Multiplexing section 109 multiplexes the received signal, the channelquality information inputted from channel quality information generatingsection 108, and the measurement-range class information inputted frommeasurement-range class control section 1401, and outputs the result toerror-correction encoding section 110.

The configuration of base station apparatus 1500 will be described nextusing FIG. 15. FIG. 15 is a block diagram showing the configuration ofbase station apparatus 1500. In base station apparatus 1500 according tothe present Embodiment 5, specific-segment allocation setting sections211 and 212 are removed from base station apparatus 200 according toEmbodiment 1 shown in FIG. 2, and measurement-range class controlsection 1501 is added as shown in FIG. 15. In FIG. 15, components thatare the same as those in FIG. 2 will be assigned the same referencenumerals without further explanations

Separation section 205 separates channel quality information andmeasurement-range class information for each subcarrier reported fromeach communication apparatus, from the received signal inputted fromerror-correction decoding section 204. Separation section 205 outputsthe separated channel quality information of each communicationapparatus to resource allocating section 206 and outputs the separatedmeasurement-range class information of each communication apparatus tomeasurement-range class control section 1501. Separation section 205also outputs the received signal after separating the channel qualityinformation and the measurement-range class information.

Measurement-range class control section 1501 stores the same informationfor selecting a measurement range as measurement-range class controlsection 1401 and selects a measurement range referring to theinformation for selecting a measurement range using themeasurement-range class information inputted from separation section205. Measurement-range class control section 1501 instructs resourceallocating section 206 to allocate resources within the selectedmeasurement range, that is, within the measurement range selected bycommunication apparatus 1400.

Resource allocating section 206 allocates resources—subcarriers—to eachcommunication apparatus based on the channel quality informationinputted from separation section 205 and information of the thresholdvalue inputted from channel quality threshold setting sections 209 and210, for the subcarriers indicated by measurement-range class controlsection 1501. Resource allocating section 206 then outputsradio-resource allocation information, which is information of theallocated subcarriers, to multiplexing section 213 and also outputs theradio-resource allocation information for each communication apparatusto transmission parameter setting sections 207 and 208.

Multiplexing section 213 multiplexes the transmission parameterinformation inputted from transmission parameter setting sections 207and 208, the radio-resource allocation information inputted fromresource allocating section 206, the QoS information, and thetransmission signal, and outputs the result to error-correction encodingsection 214. Other than the fact that measurement ranges are allocatedinstead of specific segments and measurement-range class information istransmitted instead of specific segment information, the operation ofcommunication apparatus 1400 and base station apparatus 1500 is the sameas in FIG. 10, and therefore a description of that operation will beomitted. The method for selecting subcarriers is the same as in FIG. 13,and therefore a description of that method will be omitted.

According to the present Embodiment 5, the communication terminalapparatus selects a measurement range in accordance with the allowabledelay time of the transmission data, measures channel quality for onlythe subcarriers within the selected measurement range, and reports thequality to the base station apparatus, so that it is possible to reducethe amount of control information, minimize interference with othertraffic, and prevents increases in current consumption. According to thepresent Embodiment 5, subcarriers are also divided into groups for eachmeasurement range, and the measurement range is selected according tothe delay allowance class, so that subcarrier frequency scheduling canbe accurately performed in accordance with the allowable delay time.According to the present Embodiment 5, subcarriers can be selected onlyby transmitting measurement-range class information, so that it ispossible to simplify the processing for selecting subcarriers.

The present application is based on Japanese Patent Application No.2004-319801, filed on Nov. 2, 2004, the entire content of which isexpressly incorporated by reference herein.

INDUSTRIAL APPLICABILITY

The communication apparatus and the scheduling method according to thepresent invention are suitable for applying to a communication schemeusing frequency scheduling.

1.-2. (canceled)
 3. A communication apparatus, comprising: a subcarrierselection section configured to select subcarriers from a plurality ofsubcarriers within a determined communication band based on a comparisonof an allowable delay time of data with a threshold delay time, whereina number of selected subcarriers decreases in accordance with anincrease in allowable delay time; a channel quality measurement sectionconfigured to measure channel qualities of the subcarriers selected bythe subcarrier selection section; and a report section configured toreport channel quality information including the measured channelqualities of the selected subcarriers measured by the channel qualitymeasurement section.
 4. The communication apparatus of claim 3 wherein,the subcarrier selection section is configured to select subcarrierswithin a determined period, which is specified by a specific segmentvalidity period information; the channel quality measurement section isconfigured to measure channel quality for the subcarriers selectedwithin the determined period and to measure channel quality for allsubcarriers within the determined communication band within a periodother than the determined period; and the report section is configuredto report the channel quality information of the subcarriers selectedwithin the determined period and to report, within a period other thanthe determined period, the channel quality information of allsubcarriers within the determined communication band.
 5. Thecommunication apparatus of claim 3 wherein the subcarrier selectionsection is configured to select subcarriers by selecting a group ofsubcarriers that are divided into a plurality of groups.
 6. Thecommunication apparatus of claim 3 wherein the communication apparatusis a communication terminal apparatus.
 7. A communication schedulingmethod, comprising: selecting, using a communication apparatus,subcarriers from a plurality of subcarriers within a determinedcommunication band based on a comparison of an allowable delay time ofdata with a threshold delay time, wherein a number of selectedsubcarriers decreases in accordance with an increase in allowable delaytime; measuring, using the communication apparatus, channel qualities ofthe selected subcarriers; and reporting, using the communicationapparatus, channel quality information including the measured channelqualities of the selected subcarriers.
 8. The communication schedulingmethod of claim 7 wherein, the subcarriers are selected within adetermined period, which is specified by a specific segment validityperiod information; channel qualities of the selected subcarriers aremeasured within the determined period and channel qualities of allsubcarriers within the determined communication band are measured withina period other than the determined period; and channel qualityinformation of the subcarriers selected is reported within thedetermined period and channel quality information of all subcarrierswithin the determined communication band are reported within a periodother than the determined period.
 9. The communication scheduling methodof claim 7 comprising selecting subcarriers by selecting a group ofsubcarriers that are divided into a plurality of groups.
 10. Thecommunication scheduling method of claim 7 wherein the communicationapparatus is a communication terminal apparatus.